The Effectiveness of Moringa oleifera Seed Flour and Chitosan as Coagulant‐Flocculants for Water Treatment

• Published in: Clean : soil, air, water Vol. 45; no. 8
• Main Authors: Ruelas‐Leyva, Jose P., Contreras‐Andrade, Ignacio, Sarmiento‐Sánchez, Juan I., Licea‐Claveríe, Angel, Jiménez‐Lam, Sergio A., Cristerna‐Madrigal, Yereli G., Picos‐Corrales, Lorenzo A.
• Format: Journal Article
• Language: English
• Published: 01.08.2017
• Subjects: Chitosan; Moringa oleifera; Pollutant removal; Urban river; Water treatment
• ISSN: 1863-0650; 1863-0669
• DOI: 10.1002/clen.201600339

The aim of this contribution is to provide a comprehensive comparison between chitosan and Moringa oleifera seed flour (MOSF) as coagulant‐flocculants. MOSF was obtained as a byproduct in a biodiesel process. Turbidity and heavy metal ion removal, using both eco‐friendly materials, was assessed. Jar tests were performed on samples taken from river water, agricultural wastewater, and mixed wastewater (contaminated with agricultural and urban residues). Bioflocculant dosages within the range of 0.005–20 mg L−1 were tested. Irrespective of the initial turbidity, the optimal dosage of chitosan and MOSF for decreasing turbidity in river water was 1 and 5 mg L−1, respectively. Furthermore, from river water, Pb removal up to 95% was achieved irrespective of the bioflocculant; for Mn removal, MOSF performed better than chitosan, with the adsorbent trapping close to 90% of this metal. MOSF decreased turbidity levels and heavy metal content (Mn and Pb) to under the permissible limits (Mexican environmental regulation for potable water, NOM‐127‐SSA1‐1994). Additionally, kinetic data were fitted to kinetic models of adsorption for the pollutants. For agricultural wastewater, a chitosan dosage of 10 mg L−1 reduced turbidity to 5–10 nephelometric turbidity units (NTU), and a MOSF dosage of 10 mg L−1 decreased the turbidity to values lower than 5 NTU. For the mixed wastewater, chitosan achieved a high turbidity removal, while MOSF was not suitable. Eco–friendly flocculants have been gaining attention in water remediation. This work shows a comparison between chitosan and Moringa oleifera seed flour (MOSF) as coagulant‐flocculants. MOSF was obtained as byproduct in a biodiesel process. For river water treatment, adsorption charge neutralization and sweep flocculation are assumed for chitosan and MOSF, respectively. The performance of the coagulant‐flocculant depended on the water source.